Do we have any commands like "RUN" or "STOP" in the middle of running a program

Hello, I am new to Arduino, and have lots of experience in Assembly languages. Also in Development Systems (Intel, Motorola, etc.) All of them had instructions to Stop and Start, Debug programs.
Having written a small program and when I uploaded, it immediately ran and went into loop. I could not stop the program, and have to pull the USB cable. Do we have any means like that in Arduino Uno?
Thank, and your reply is greatly appreciated.

Thanks for the reply. How does one exit from running programs? Do we have to kill the power?

If you are asking about the Arduino IDE, no, there is no way to set breakpoints or single step.

You can do things like

while (digitalRead(pinX) == 1){
//hang out until pinX is grounded

then the program will stop and wait until a pulled up pin is grounded with a momentary button.
You can add some Serial.print's to your code to show variable values or similar.

Thanks very much for the reply.

you upload the written program, does it run immediately?
How does one exit from running program? Do we have to kill the power to stop?

Thanks very much for the valuable advice. I shall incorporate in the future programs if I want to run one cycle.
Greatly appreciated